A rapid, sustainable, and efficient analytical method based on Rotating Disk Sorptive–Dispersive Extraction (RDSDE) coupled to HPLC–DAD was developed and validated for the determination of florfenicol in animal plasma. The method employs a magnetic activated carbon (MAC) sorbent derived from avocado seed, an agricultural waste material, combining high extraction efficiency with improved environmental performance. Key extraction parameters were optimized, achieving optimal conditions with 20 mg of MAC, an extraction time of 20 min, and acetone as desorption solvent with a desorption time of 5 min.The method was fully validated in porcine plasma, demonstrating excellent selectivity, linearity (R² ≥ 0.9967), precision (RSD ≤ 7.2%), and accuracy (recovery ≥ 91%) over the concentration range of 0.5–10 mg L⁻¹. Dilution integrity was confirmed up to 20 mg L⁻¹, and robustness was demonstrated with respect to sorbent batch variability. Applicability to bovine plasma was also verified, confirming the method’s robustness toward matrix variation.A kinetic comparison between RDSDE and conventional Rotating Disk Sorptive Extraction (RDSE) revealed markedly faster extraction kinetics for RDSDE, reaching equilibrium within 20 min, whereas RDSE required substantially longer extraction times under comparable conditions. In addition to its analytical performance, the method was evaluated using AGREE, AGREEprep, BAGI, and RAPI metrics, confirming its classification as a white analytical method that balances metrological robustness, environmental sustainability, and operational practicality.Overall, the proposed RDSDE followed by HPLC-DAD methodology represents a technically innovative and environmentally responsible alternative for florfenicol determination in animal plasma, offering significant advantages for veterinary pharmacokinetic studies and residue monitoring.

Both synthetic and natural hormones-17 alpha-ethinylestradiol (EE2), 17 beta-estradiol (E2), and estriol (E3)-are present in wastewater samples in concentrations typically expressed in ng L-1. These concentrations are significant, as the presence of such hormones in water sources poses risks to both living organisms and the environment. Steroidal hormones from human sources are categorized as emerging pollutants and endocrine-disrupting compounds (EDCs), which constitute a health hazard. In this study, the Rotating Disk Sorption Extraction (RDSE) method was used with modified clays incorporating ionic liquids to detect estrogenic hormones in hospital wastewater treatment plant (HWWTP) samples. Sodium montmorillonite was modified to enhance its extractive capacity by intercalating ionic liquids ([C16MIM+][anion-], where anion = Br-, OH-, or BF4-) between its interlayers. Following extraction, the concentrated analytes were measured using liquid chromatography coupled with photodiode array detection (HPLC-PDA). The method achieved absolute recoveries of 61 % for EE2, 41 % for E2, and 20 % for E3; these recoveries were lower than those obtained with a commercial C18 sorbent. However, the technique achieved enrichment factors of 13, 23, and 32 for E3, EE2, and E2, respectively. In wastewater, the intra-disk reproducibility (RSD) was below 12 %. The method also provided limits of detection and quantification in HWWTP samples of 0.18-0.42 ng mL-1 for E3, 0.15-0.37 ng mL-1 for E2, and 0.07-0.16 ng mL-1 for EE2 when using the modified adsorbents. Average concentrations in hospital wastewater were measured at 4.30, 3.85, and 7.23 ng mL-1 in the influent (before treatment) and 3.81, 1.33, and 4.00 ng mL-1 in the effluent (after treatment) for E3, E2, and EE2, respectively.

BACKGROUND:A new approach based on Stir Bar Sorptive Dispersive Microextraction (SBSDME), termed Rotating Disk Sorptive Dispersive Extraction (RDSDE), was developed to confirm and quantify the kinetic advantages of sorbent-based dispersive techniques compared to their non-dispersive counterparts. Among non-dispersive techniques, Rotating Disk Sorptive Extraction (RDSE) allows for a direct comparison with its dispersive counterpart, as the sorbent phase in RDSE can be confined within the disk cavity using the exact same amount as in the dispersive mode. This comparison is not feasible in stir bar sorptive extraction. RESULTS:The advantages of RDSE combined with the dispersion of magnetic sorbent materials were explored using RDSDE technology. Magnetic activated carbon (MAC) derived from avocado seeds was used as the sorbent, with triclosan (TCS), bisphenol A (BPA), ibuprofen (IBU), and 1-hydroxy-ibuprofen (1-OH-IBU) as representative analytes. The RDSDE method was optimized for efficiency and speed. Optimal conditions were: 10 mg of MAC, 20 min extraction at pH 2, acetone as desorption solvent and 10 min desorption. These parameters provided the best analytical response with minimal time and resource use. The method was then validated, and a kinetic comparison was performed. The results demonstrated that RDSDE reaches extraction equilibrium in approximately 20 min, significantly faster than RDSE. The initial extraction velocities were between 12 times higher for BPA and 43 times higher for IBU in the dispersive mode. SIGNIFICANCE:The kinetic comparison clearly shows that RDSDE is a more efficient extraction technique due to its rapid extraction equilibrium. The dispersive mechanism plays a crucial role in accelerating analyte extraction, as evidenced by the steeper extraction profiles of RDSDE compared to RDSE. Importantly, this study presents the first direct kinetic comparison between RDSDE and conventional RDSE, highlighting the novelty of the approach. This underscores the potential of RDSDE as a faster and more efficient method for extracting target compounds from aqueous samples, offering significant advantages in analytical performance and operational efficiency.

A novel chitosan-biochar biocomposite was engineered as a synergistic and sustainable sorbent phase for the extraction of carbamazepine and its metabolites from environmental waters. The material was prepared using citric acid as a green crosslinker and glycerol as a plasticizer. Its formulation was optimized through experimental design. Compared with crosslinked chitosan and biochar, the biocomposite exhibited superior extraction performance. Mathematical modeling, together with complementary characterization analyses, corroborated this enhancement, which revealed a synergistic hybrid effect involving multi-site interactions beyond surface area contributions. Sustainability was demonstrated by the use of renewable precursors, along with a comprehensive assessment of biodegradability, biocompatibility, and toxicity of the constituents, reusability over multiple extraction-desorption cycles, and the application of analytical greenness metrics. Applied in rotating-disk sorptive extraction, the optimized methodology achieved high recoveries (86-96 %), with low relative standard deviations (<16 %), and sub-μg L-1 limits of detection, performing comparably to commercial sorbent phases and outperforming others. The method enabled the determination of the analytes in river water, confirming the potential of this material as a cost-effective, sustainable, and high-performance material for environmental monitoring.

In the realm of green analytical chemistry, there is growing interest in sorbent phases derived from natural materials like grapefruit peels as promising alternatives to commercial sorbent phases. Initially, the effectiveness of grapefruit peels in their natural state was compared to activated carbons treated with activating agents as a sorbent phase in rotating disk sorptive extraction (RDSE). The conditions for synthesizing activated carbon were optimized by adjusting the activating agent variables, proportions, and temperatures to obtain an efficient material for extracting ethylparaben (EP), propylparaben (PP), ibuprofen (Ibu), triclosan (TCS), bisphenol A (BPA), and 17-alpha-ethinylestradiol (EE2) using rotating disk sorption extraction technique from aqueous samples. The optimal conditions were determined to be activation with ZnCl2 at a 1:1.2 ratio (material: activating reagent) and carbonization at 400 degrees C (AC400(Z1.2)). Characterization revealed a hydrophilic microporous material with a large surface area and aromatic structure, confirming its potential as a sorbent phase for aqueous sample preparation. The application of AC400(Z1.2) sorbent phase in RDSE in river water confirmed its effectiveness, revealing EP, PP, Ibu, TCS, and BPA in concentrations ranging from 0.18 to 2.8 mu g L-1, with EE2 concentration below the limit of detection. Reusability studies demonstrate that this material can be reused for the simultaneous extraction of analytes in at least two consecutive extractions without requiring additional treatment between extractions. This material proves to be an economical and bio-based alternative to commercial sorbent phases. Finally, its application in RDSE was evaluated using green analytical chemistry metrics (AGREEprep and BAGI), resulting in a methodology with a low environmental impact.

Microextraction technologies emerged as an attractive and eco-efficient alternative in sample preparation with the advent of solid-phase microextraction (SPME).1 The sensitivity and precision of methodologies based on microextraction are improving due to the ease of preconcentration and automation capacity that they provide, respectively. Furthermore, the miniaturization and eco-efficiency have improved considerably by using less space and avoiding the use of toxic reagents and high volumes of organic solvents. From the 1990s until the present, SPME has continued to evolve, becoming commercially available for many chromatographic applications. Also in this period, stir bar sorptive extraction (SBSE) has become another commercially available alternative,2 with the extraction device offering a greater volume of sorbent phase compared to SPME. Simultaneously, other novel microextraction techniques have emerged that complement some of the drawbacks of SBSE.3 Among these microextraction techniques, rotating-disk sorptive extraction (RDSE) was proposed by our research group in 2009 and has been recently reviewed, considering all its advances and applications.4,5 The heart of all microextraction technologies is the nature of the sorbent phase. In the context of solid sorbents, they can be classified as synthetic or natural materials according to their origin (Figure 1). Typical examples of synthetic sorbents range from the most hydrophobic octadecyl (C18) to the ion exchange phases, most of them being commercially available. Sorbents of intermediate polarity (hydrophilic–lipophilic balance) and hydrophilic-like silica-based sorbents are also commercially available. In the specific case of emerging contaminants, the copolymer of divinylbenzene and N-vinylpyrrolidone (OasisTM HLB) has largely been used, considering that its hydrophilic–lipophilic balance allows various sorption interactions with emerging contaminants. Among them, hydrophobic interactions occur through -stacking and polar interactions occur via hydrogen bonding. The hydrophilic–lipophilic balance typical of OasisTM HLB has encouraged its use in RDSE as a sorbent in multiresidue analysis.6,7 Although sorbents based on these commercial polymers are being used in different microextraction techniques, some trends are currently being claimed in the design of solid sorbents by considering new synthetic materials. In this context, micro- and nanomaterials have been tested, such as carbon nanotubes, graphene and fullerenes.8 Interactions via delocalized -electrons are especially important for molecules containing aromatic rings, as in the case of emerging contaminants. Other nonconventional materials9 that are being actively studied as synthetic sorbents are porous solids such as metal organic frameworks, covalent organic frameworks and layered double hydroxides. Together with these sorbent developments, the innovation in materials of natural origin, which can be recycled, is another parallel trend in analytical chemistry and is the central idea to be addressed in the current research of our team. As mentioned previously, a current challenge in analytical chemistry is to emphasize the use of eco-efficient or green analytical processes, positioning this characteristic at the same level as the sensitivity and selectivity of the measurement. Microextraction technology is green per se, given the minimization of the consumption of organic solvents in the sample preparation stage. However, an even higher level of analytical eco-efficiency (or greenness) is achieved when the sorbent phase used is of natural origin; in this way, the use of natural materials is in line with the change of the paradigm of typical production models (take–make–dispose) towards a circular model of waste reuse.10 Sorbents of natural origin can be classified according to their chemical composition as inorganic and organic sorbents. Clay is an example of an inorganic sorbent that plays an important role in the retention/mobility behavior of chemicals in the soil. Consequently, materials based on clay have been proposed as sorbents in different microextraction devices.11 Clays can also be modified to decrease their polarity for use in the sorption of hydrophobic analytes.11,12 Natural organic sorbents, also called biopolymeric sorbents, can be classified by their origin as natural polymers of plant origin (polysaccharides, proteins, polyesters), animal origin (polysaccharides, proteins, resins) and microbial origin (polysaccharides, polyesters, polyamides, polyanhydrides).13 All these materials prepared from natural biopolymers have been studied and proposed primarily in water treatment technologies; however, they could also be considered in the field of analytical chemistry as microextraction/extraction sorbents. The main novelty of this idea is that it is only recently, and in only a few cases, that these sorbents been used in microextraction technology, with wide future perspectives being expected.10,13 These natural materials can also be modified through known reactions of functionalization (selective oxidation, esterification, crosslinking, copolymerization, etc.). Such modifications reinforce the potential of the functional group and the number of active sites of the sorption material.14 In addition, modification of the natural materials can be achieved by pyrolysis to produce biochar. During the pyrolysis process, the components are thermally decomposed at different temperatures and times, expanding their porosity. Besides to increase the degree of aromatic condensation and aromaticity, typical functionalities present on the biochar surface include hydroxyl, carboxylic, lactone, amine and amide moieties, which are the key to its sorptive properties15 and the retention of pollutants of different natures. Similarly, from these natural materials, activated carbon can be generated at a significantly lower cost than from the same commercial substrate. To prepare activated carbon from these natural materials, two basic steps are required: pyrolysis of the raw material; and activation. Pyrolysis in the temperature range of 300–900 °C produces biochar with the required porosity associated with high carbon content. The activation step then provides a material with a higher surface area, generating additional porosity, and allows adjustment of the chemical surface to produce unique characteristics.16 During recent years, our research group has been contributing to this research field by designing new natural sorbent phases to be applied in the microextraction of emerging contaminants from wastewater and river water. Some examples of natural sorbent phases implemented in our laboratory are peanut shells,17 cork,18 avocado seed19 and chitosan.20 In various instances, these materials or their derivatives have shown comparative sorption behavior with commercial sorbents such as OasisTM HLB. By using these natural sorbents, emerging contaminants have been quantified in wastewater and river water samples from the metropolitan region of Chile.

A novel strategy for microextraction of emerging contaminants was developed by using cork activated carbon (CAC) as the sorbent phase. Carbonization of the natural phase increased the surface area and the porosity of the material, thus improving the extraction efficiency. Moderately polar compounds, such as ibuprofen and its metabolites, were used as model analytes in water samples. Rotating disk sorptive extraction (RDSE) together with gas chromatography‒mass spectrometry (GC‒MS) were used for extraction and determination of the analytes, respectively. The optimum conditions for the material synthesis were 600 °C, K2CO3 as the activating agent and a mass ratio of 0.8:1 (activating agent:raw material). The optimum values for the RDSE were pH 2, a sample volume of 25 mL and an extraction time of 90 min. The absolute recovery rates for ibuprofen and its metabolites ranged from 19 to 55%, and the relative standard deviations were between 3 and 13%. The proposed method was used to measure the analytes in the influent and effluent from a wastewater treatment plant in Santiago, Chile. The concentrations found for ibuprofen and its metabolites were 0.98–9.8 µg L-1 and 0.8–8.6 µg L-1 in the influent and effluent, respectively. Activation of the cork material enabled the synthesis of a sorbent phase with sorption efficiencies similar to those obtained with the commercial octadecylsilane (C18) phase and superior to that observed for styrene-divinylbenzene (S-DVB). This process is simple and cost-effective.

According to green analytical chemistry principles, the use of agricultural byproducts as sorbent phases is an interesting topic due to their lignocellulosic origin, as they are biodegradable and inexpensive. To the best of our knowledge, this is the first study in which avocado seed and avocado seed activated carbon are proposed as sustainable sorbents for solid-phase microextraction technologies, which were used to assess the proof of concept. Rotating disk sorptive extraction (RDSE) was used as a model technology and ibuprofen (Ibu) and 1-hydroxy-ibuprofen (1-OH-Ibu) as representative analytes. It was found that activated carbon (AC) prepared at 600 °C with an impregnation ratio (raw material/activating agent (ZnCl2), w/w) of 1:1.2 had better extraction efficiency than other ACs obtained at different temperatures, impregnation ratios, and activating agents (K2CO3). Characterization revealed several differences between natural avocado seed, biochar prepared at 600 °C, and selected AC since the typical functional groups of the natural starting material begin to disappear with pyrolysis and increasing the surface area and pore volume, suggesting that the main interactions between analytes and the sorbent material are pore filling and π-π stacking. By using this AC as the sorbent phase, the optimal extraction conditions in RDSE were as follows: the use of 50 mg of sorbent in the disk, 30 mL of sample volume, pH 4, 90 min of extraction time at a rotation velocity of the disk of 2000 rpm, and methanol as the elution solvent. The extracts were analyzed via gas chromatography coupled to mass spectrometry (GC–MS). The method provided limits of detection of 0.23 and 0.07 µg L−1 and recoveries of 81

Background: Developing highly sensitive and selective measurement techniques to detect trace compounds in diverse matrices is a significant challenge in analytical chemistry. These techniques must adhere to green chemistry principles by minimizing organic solvent use, simplifying sample preparation, and streamlining process steps. Additionally, there is a growing need for sustainable analytical methods due to increased environmental awareness. The problem addressed in this work is the need for an eco-friendly and efficient method for the extraction and detection of trace organochlorine pesticides in water samples. Results: We employed SPME using a novel clay thin film sorbent, deposited on a nickel-titanium alloy wire via magnetron sputtering. Montmorillonite clay was chosen for its excellent adsorption properties and eco-friendly nature, aligning with green chemistry principles. The approach involved coating the SPME fiber with hydrophobic modified montmorillonite clay, followed by silylation. The method was tested for extracting 12 model organochlorine pesticides, including BHC, lindane, and DDT, demonstrating high isolation efficiency. The coated thin film and its silylation modification were characterized using standard spectroscopic techniques, confirming the successful creation of a new adsorbent phase. The direct immersion SPME approach achieved relative recoveries ranging from 65 % to 99 %, with reproducibility (RSD) below 6 %. This method provided low detection limits (10-15 ng L- 1 ) and quantitation limits (32-50 ng L- 1 ). Significance: Our approach offers an eco-friendly, highly efficient solution for the extraction and detection of trace organochlorine pesticides. The significant improvement in recovery rates and reproducibility, combined with low detection and quantitation limits, underscores the potential of this method to enhance analytical practices in environmental monitoring and public health. Furthermore, the use of sustainable materials and processes aligns with global efforts to reduce environmental impact in analytical chemistry.

The use of agricultural byproducts for the development of new sorbent phases has become increasingly popular among the scientific community of analytical chemists due to the intrinsic properties of these materials, including biodegradability, nontoxicity and biocompatibility. In the current research, peanut shells, peanut shell biochar and activated carbon were assessed as microextraction sorptive phases by using rotating disk sorptive extraction of emerging contaminants covering a range of polarities (ethyl paraben, diclofenac, triclosan, bisphenol A, and 17-alpha-ethinylestradiol) and subsequent detection by gas chromatography coupled to mass spectrometry (GC-MS). It was demonstrated that, independent of the polarity of the analyte, the extracting capacities of the activated carbon were superior to those of biochar and the untreated phase. The three sorptive phases were characterized by different techniques. SEM micrographs show the absence of pores in the untreated phase, which changes substantially after pyrolysis. The activated carbon exhibited a BET area of 516 m(2) g(-1) and a pore size and total pore volume of 2.12 nm and 0.27 cm(3) g(-1), respectively. The high porosity and some characteristic signals in the FTIR spectra suggest that the main interactions of activated carbons with analytes are pore filling and pi-pi stacking. Optimization studies showed that the optimal conditions for extraction were 10 mg of sorptive phase, pH 2, 70 min of extraction time, 15 mL of sample volume, 2000 rpm rotating velocity, and ethyl acetate as the elution solvent. The validation showed limits of detection between 0.003 and 0.729 mu g L-1, absolute recoveries ranging between 16 and 87% and relative standard deviations below 10%. A comparative study using the same extraction technology but with commercial phases demonstrated that activated carbon achieves comparable or higher extraction efficiencies for this set of analytes.

A mixture of n-octanol and dithizone was introduced as an effective and novel extraction agent in a thin-film microextraction technique for the pre-concentration of cadmium ions. The extraction agent was immobilized on small pieces of porous polypropylene flat membrane as a supported liquid membrane. The analyte extraction was performed by immersing the modified film in the sample solution, and via a complex formation between the immobilized dithizone on the film and cadmium ions. After the thin-film microextraction process, the colored cadmium-dithizone complex was directly measured by a smartphone colorimetric analysis. Under optimized conditions, the linear dynamic range, the limit of detection, and the limit of quantification were 0.5-300.0, 0.1, and 0.4 μg L-1, respectively. The developed technique was successfully employed to quantify cadmium ions in water and food samples. The high relative recovery values (95.0-103.0%) along with relative standard deviations of less than 2.5% were obtained for the spiked samples.

The features and nature of the sorptive phase may be the stage that determines the scope of microextraction techniques. In search of new alternatives, materials of natural origin have recently been explored to establish greener analytical strategies. Based on that search, this research proposes the use of chitosan as a sorptive phase, which was assessed in the rotating disk sorptive extraction of emerging contaminants from aqueous systems. Chitosan is a biopolymer of animal origin that is usually found in the shells of crustaceans. The main charac-teristic of this material is the presence of a high number of nitrogenous groups, which gives it high reactivity, but its main disadvantage is associated with its high swelling capacity.In this research, chitosan was crosslinked with a low concentration of glutaraldehyde to form thin films that were easily immobilized on the surface of the rotating disk. The main advantage of this modification is the considerable decrease in the swelling capacity, which prevents loss and rupture of the sorbent during high rotation of the disk. In addition, it not only improved the physical characteristics of chitosan but also increased its extraction capacity. With regard to its use as a sorptive phase, all the variables associated with the micro-extraction of the analytes were studied, and optimal variables were found to be: pH 4, 20% NaCl (salting out effect), 30-45 min as equilibrium time and elution of analytes with a mixture of methanol:ethyl acetate (1:1).Validation of the methodology for the determination of methyl triclosan and triclosan was carried out, and relative recoveries between 89 and 96% and relative standard deviations less than 14% were found. The detection limits were 0.11 and 0.20 mu g L-1, respectively. Through its application in real samples (natural and residual waters), triclosan was quantified between 0.7 and 1.3 mu g L 1. Finally, the "green" properties of the phase were evaluated, demonstrating that it is reusable for at least three cycles and biodegradable. Compared to its efficiency with a commercial phase (in this case, the styrene divinyl benzene phase), the proposed biosorbent provided a similar and even higher sorptive capacity (depending on the analyte).

The matrix of certain complex samples represents a great challenge in microextraction technology due to its ability to interfere with some step of the sample preparation procedure or in the detection itself. Normally, a suppression of the analytical signal occurs by the presence of certain components of the matrix, which tend to be coextracted with the analytes under study. Urine represents one of these complex matrices. The yellow coloration of urine comes from a main pigment known as urobilin, which can persist in all final extracts after sample treatment and has been correlated with the impossibility of correctly measuring the analytes. In the present study, we propose the determination of estrogens and their hydroxylated metabolites in urine by integration of a dispersive solid phase extraction (d-SPE) to eliminate the matrix effect with the rotating disk sorptive extraction (RDSE) of the analytes, prior to their determination by liquid chromatography/mass spectrometry.The proposed dispersive phase was primary-secondary amine (PSA), which, due to its physicochemical characteristics, allows the extraction of polar compounds (such as urobilin). Estrogens and their hydroxylated metabolites, being molecules of lower polarity, were demonstrated not to be removed by PSA and were extracted only by the styrene-divinylbenzene phase supported in the rotating disk. The amount of dispersive phase was optimized, finding that 300 mg is the best analytical response for 2 mL of urine sample. The equilibrium time for the extraction of the analytes was 60 min.Matrix-matched calibration was used for quantification, obtaining correlation coefficients greater than 0.99, limits of detection and quantification between 0.10 and 0.13 and 0.3-0.5 mu g/L, respectively, and recoveries between 72 and 130 % with precision, expressed as relative standard deviation, between 8 and 17 %. The matrix effect was reduced significantly between-24 and-48 % (without the use of d-SPE, most of the analytes were not detected). In addition, the proposed method was applied to the determination of the analytes in real urine samples of different persons. Finally, through enzymatic hydrolysis, it was possible to quantify estrogens and their hydroxylated metabolites in urine samples, both in their total form and in their naturally conjugated form.

Triclosan (TCS) is an antibacterial compound used mainly in personal care products. Its widespread use for decades has made it one of the most widely detected compounds in environmental matrices and in biological fluids. Although it has been shown to be an endocrine disruptor in rats and aquatic species, its safe use by humans is unclear. The aim of the present study was to evaluate the effects of exposure to TCS in female rats. To this end, 14 rats were divided into two groups and fed daily as follows: the control group with sesame oil and the TCS group at a dose of 50 mg/kg/day for 28 days. Any signs of toxicity in the rats were observed daily, and the weight and phase of the estrous cycle were recorded. At the end, the rats were decapitated, the serum and ovaries were collected. The levels of testosterone and progesterone in serum were determined by immunoassay and mass spectrometry. Estradiol (in serum) and kisspeptin-10 (in serum and ovary) were measured only by immunoassays. Trace elements were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The weight gain study of the rats showed a significant decrease by exposure to TCS, while the estrous cycle was not significantly affected compared to the control. The optimized methods based on mass spectrometry showed a significant decrease in the levels of progesterone and testosterone due to exposure to TCS. In addition, elements determined by ICP-MS in rat serum showed significant changes in calcium, lithium and aluminum due to TCS treatment. Finally, the kisspeptin-10 levels did not show a negative effect due to the treatment by TCS. The results suggest that medium-term exposure to TCS did not significantly alter estrous cyclicity but caused alterations in growth, sex hormone levels and some elements in the rat serum.

Novel passive samplers based on cork as a sorbent phase were implemented for the sampling and preconcentration of triclosan in water. Two sampler configurations were developed: The larger sampler (cork passive sampler, CPS) involved a Teflon casing to protect a circular laminar cork phase with a diameter of 4.5 cm, which was covered by polyethersulfone membranes. In the smaller sampler (miniaturized cork sampler, MCS), a circular piece of cork with a diameter of 0.8 cm was directly exposed in the water samples.The sampling rates were calculated through static kinetic calibration tests in the laboratory, and linearity was observed in the kinetic part of the absorption (or depletion) curve. The sampling rates were 0.47 L d −1 and 3.9 × 10−4 min−1 for CPS and MCS, respectively. The difference in these values was attributable to the substantial variation in the surface area of the exposed sorbent phase (approximately 25 times). Compared with that associated with existing passive devices, the use of cork in passive sampling devices yielded larger values of sampling rates in several cases. The samplers presented isotropy, which suggested uniform sorption and desorption capacities.The samplers were tested in the field to quantify the amount of triclosan in wastewater and river water at points near a wastewater treatment plant. The triclosan content was 19–390 and 7–271 ng L-1 for wastewater and river water, respectively. The persistence and increase in the triclosan level indicates that its use continues to be pervasive without any regulation. The proposed samplers based on cork represent an ecofriendly, efficient, low-cost and easily accessible alternative to monitor triclosan over long periods.

Phthalateacid esters (PAEs) concentration in bottled water and different factors (water pH, storage time, sunlight exposure, and temperature) that affect/control them have become hot topics during recent years. Nevertheless, quite contradictory results and disagreements on the effects of these factors have been published. In an attempt to find some consensus on this topic, a comprehensive study considering the combined effect of long storage times (longer than a year) and the water hydrochemical signature (including water pH, elemental composition and the presence/absence of dissolved CO2)was performedusing the four most commonly consumed bottled water brands on the Chilean market. Each water brand was analyzed between 10 or 14 different times, depending on the brand (in total 97 samples were studied). Following the concept ofthe hydrochemical signature typically used in hydrogeology to classify types of waters, the notion of a water phthalate fingerprint was proposed. Finally, concerning the effect of long storage times, this study demonstrates that all the trends (increase, decrease or steady) of the Total PAEs concentration are possible; and these trends are controlled by the specific hydrochemical signatureandphthalate fingerprint of the bottled water.

Ibuprofen is one of the most widely used nonsteroidal anti-inflammatory drugs due to its analgesic, anti-inflammatory and antipyretic properties, as well as its low cost and easy accessibility. A fraction of the compound and its metabolites are excreted in the urine, being eliminated in the wastewater reaching river waters in the range of ng L-1 to mu g L-1. In this context, highly sensitive and selective analytical methods are required to quantify them, including these methods a pre-concentration step. In this work, the use of a microextraction technology based on rotating-disk sorptive extraction, involving a sorptive phase of laminar cork, was implemented for the extraction of ibuprofen and 1-hydroxyibuprofen from aqueous samples and their subsequent determination by gas chromatography coupled to mass spectrometry.The optimal conditions for determination of the analytes were: 20 mL of sample volume, pH 2, 20 % w/v NaCl (to increase the ionic strength), 90 min of extraction time and 2000 rpm of rotation velocity of the disk. Recoveries of 118 and 39 % and relative standard deviations of 6 and 13 % for ibuprofen and 1-hydroxyibuprofen were obtained, respectively. The presence of both compounds in river waters (Mapocho river, Santiago of Chile) at a concentration of 2.56 to 4.08 mu g L-1 were found. The use of laminar cork as a natural sorbent phase immobilized in the rotating-disk allowed to extract the analytes from water samples through its lipophilic-hydrophilic balance that favors the interaction with the compounds under study.

For me, being the Director of CENMA was a very important challenge because it involved setting up and then running a very complete analytical lab in all areas of the environment and with the best equipment in the country, together with a team of carefully selected young chemists from the country.

A critical review of rotating-disk sorptive extraction (RDSE) is presented. This review reports the principles of RDSE regarding fundamentals, evolution and applications. RDSE is based on the extraction equilibrium between a sorptive phase and an aqueous phase that are in continuous contact and movement during extraction. The main advantage of this technique is the high mass transfer between the phases, which is achieved by the ability to reach high rotational velocities without tearing the extraction device. In addition, the great versatility of RDSE in the study of hydrophobic and hydrophilic analytes is evidenced considering the ease of immobilization of different sorptive phases in both laminar and particulate forms. RDSE is mainly coupled to chromatography; however, combination with spectroscopic techniques is also possible, allowing for measurements directly on the phase. Furthermore, automation through continuous flow systems has also been implemented in RDSE and in bioavailability studies.